Re: Newbie Questions On Corks, etc. ?

Jose wrote:
>> Jose wrote:
>>> The reason to store wine bottles sideways
>>> does not exist with screwcaps.
>>> I store them upright, filled to the brim.
>> OK for vertical storage, same here, but you cannot have them filled to
>> the brim, the expansion with heat will cause the closure to leak much
as
>> the corks would have been pushed out. You still need an expansion
space.
> 
> Never thought of that.  But haven't had a problem, perhaps because I
keep 
> them in the fridge, where temperature is pretty constant (and so far, 
> I've only used screwcaps for whites, which are rebottled at fridge 
> temperature).
> 
> Anybody know the coefficient of expansion for wine?

Bottle glass has a coefficient of volume expansion around 20 x 10^-6 
1/C°. Alcohol is around 750 x 10^-6 1/C°.

Water is a bit funny as it expands both above and below 4°C but curves 
are readily available on the net. At 4°C density is 1.0000 g/ml, at 40°C

it is 0.9922 g/ml.

Assume we have exactly 750ml of  wine with 13% alcohol by volume at 4°C, 
this means 97.5 ml of alcohol and 652.5 ml of water. By bringing it from 
4°C to 40°C:
- the glass expands by 20 x 10^-6 1/C° x 750 ml x (40-4)°C = 0.54 ml
- the alcohol expands by 750 x 10^-6 1/C° x 97.5ml x (40-4)°C = 2.63 ml
- the water expands by (1/0.9922 - 1.0000)ml/g x 652.5g = 5.13 ml

Net effect is an "overflow" of 5.13 + 2.63 - 0.54 = 7.22 ml.

With a standard neck diameter of 1.85cm, this means the liquid will push 
up the neck by 2.67 cm, just over an inch. Much more if it is a high 
octane zin :-)

Now if you fill to the rim, something will have to give to accomodate 
the extra 7ml of wine, either the bottle will explode or the Stelvin 
closure will leak.

Note how the alcohol is a significant contributor to expansion. If you 
did the same example with 40% whiskey, the expansion would be 11 ml, or 
4cm up the neck. This may explain why most liquor bottles, while having 
the same diameter at the cork, are much wider just below the cork, they 
seem to have a kind of bulge for better expansion capability.

-- 
Mike Tommasi - Six Fours, France
email link http://www.tommasi.org/mymail